The present invention relates to water extractors and, more particularly, to a water extractor that incorporates an upstream air-water droplet swirl-imparting mechanism with a plurality of downstream water droplet collection zones for capturing water droplets.
Water extractors are generally used for removing water droplets from an airstream. Such devices are typically used in an environmental control system (ECS) which supplies cool dry air to the cabin or passenger compartment of an aircraft. Generally, humid air for this purpose is obtained in a heated condition from the engines or the auxiliary power unit of the aircraft. As the humid air cools, as for example after being passed through a condenser, water vapor condenses into liquid. It is highly desirable that the water liquid droplets be removed from the air stream before the air is routed to the cabin or passenger compartment, because unless the moisture is removed, the water liquid droplets will reduce the efficiency of the system, cause icing problems when the air is at subfreezing temperatures, cause fog in the aircraft ducts, cabin and flight deck, and corrode system components.
Various prior art water extractors have been used in removing water from moisture-laden air. Exemplary of such devices are those shown in U.S. Pat. No. 4,681,610 to Warner and U.S. Pat. No. 5,885,333 to Dix. Both of these patents disclose high performance water collectors. However, the shape and size of these water extractors, as well as their installation requirements, do not lend themselves to the current needs of aircraft environmental control systems because, as a rule, existing designs for water vapor extractors require a minimum length, based on a typical length to diameter ratio, that exceeds the available installation space for newer aircraft air-conditioning systems or environmental control systems. This dimensional constraint leads to a substantial deficiency in the water removal performance which, in turn, results in diminished cooling performance otherwise required to meet the output needs for the aircraft cabin application.
Therefore, there exists a need for an apparatus and method for providing a water extractor that can attain an optimum flow rate within the physical constraints of a small space available for installation.
In one aspect of the present invention, a water extractor comprises a housing through which moisture-laden air flows where the housing includes a swirl-imparting member at an entrance to the housing, and two water extracting assemblies axially spaced from one another and located downstream from the swirl-imparting member.
In another aspect of the present invention, a method of treating a water-laden air stream to remove water droplets therefrom comprises imparting a swirling, centrifugal motion to the air stream at a first station near the entrance of a water extractor housing; and then removing water droplets from the air stream at two additional, axially separated, stations in the water extractor housing downstream from the first station. One of the two stations includes an axially extensive perforated section of the housing wall, and the other of the two stations includes an upstream-facing flange of smaller diameter than that of the housing for removing water droplets not captured at the first station.
Other aspects, advantages and features of the invention will become more apparent and better understood, as will equivalent structures which are intended to be covered herein, with the teaching of the principles of the invention in connection with the disclosure of the preferred embodiments thereof in the specification, claims and drawings.